[U-Boot] [PATCH v2 08/13] usb: gadget: ether: Provide a way to read MAC address

[Simon Glass]

Hi Lukasz,

On 21 June 2017 at 01:33, Lukasz Majewski <lukma at denx.de> wrote:
> Hi Vignesh,
>
>> Hi Lukasz,
>>
>> On Thursday 15 June 2017 10:28 PM, Marek Vasut wrote:
>> > On 06/14/2017 02:24 PM, Vignesh R wrote:
>> >>
>> >>
>> >> On Tuesday 13 June 2017 07:36 PM, Marek Vasut wrote:
>> >>> On 06/13/2017 02:10 PM, Vignesh R wrote:
>> >>>> Provide a way to read MAC address for usb_ether device from board
>> >>>> function. Board files can override board_set_usbnet_devaddr() to
>> >>>> populate MAC address to be used by usb_ether as device address.
>> >>>>
>> >>>> Signed-off-by: Vignesh R <vigneshr at ti.com>
>> >>>
>> >>> This patch is totally unrelated to this series.
>> >>
>> >> This series converts dwc3 peripheral to device model and the best
>> >> way to test this on TI platform to use it on ether gadget and test
>> >> RNDIS boot. Hence, I had to do patches 8 to 13. Therefore I posted
>> >> them together for completeness, if somebody wanted to test this
>> >> out.
>> >
>> > Testing is great, but this is probably a fix and it's unrelated to
>> > the series anyway.
>> >
>> >>> Moreover, just set eth*addr using setenv() to achieve the same
>> >>> iirc .
>> >>>
>> >>
>> >> eth*addr is used for regular ethernet interface and usually set by
>> >> regular ethernet driver, but I could not find a way to set MAC
>> >> address for usb ethernet interface
>> >> Board file will now override board_set_usbnet_devaddr() to read
>> >> MAC and then call setenv()
>> >
>> > Lukasz should be able to jump in and help.
>> >
>>
>> Any preference on how to handle this?
>> Basically, I need a way to pass MAC address to usb_ether driver. MAC
>> address is available in specific efuse registers.
>
> It seems to me like we need to read some board specific code anyway
> (because the efused data can be placed at different addresses for
> different SoC - e.g. am4xx or dra7).

If it is just a different address then that could be described in the
device tree.

>
> The __weak function could check if e.g. "ethusbaddr" is set and read eth
> addr (if one would like to override it from envs).
>
> And as far as I remember TI even for "ordinary" ETH driver reads data
> (MAC addr) in board file, so there should be no problem for also
> reading ETH data from there.

Rather than a weak function could we provide a misc 'driver' which
other drivers can call when they need information? We could use an
ioctl-like interface perhaps, if it is not worth adding a new uclass
methods for this. Or perhaps we could have a UCLASS_BOARD with methods
like get_mac_addr(). The the board could provide a driver.

We should not be needing weak functions with driver model - it tends
to create a sloppy API IMO and makes it hard to know what code is
called.

>
>> Previously, this was
>> handled by board_eth_init(), this is no longer available when using DM
>> based ethernet driver.
>>
>>
>
>
>
>
> Best regards,
>
> Lukasz Majewski
>
> --
>
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Regards,
Simon